[PATCH] powerpc/pseries: lparcfg - fix kbuf[] underflow

George Wilson <[email protected]>
Newsgroups org.kernel.vger.stable
Message-ID <[email protected]>
In lparcfg_write(), a count of 0 results in kbuf[] being indexed at -1.
Check for count == 0 in the existing check for count > sizeof(kbuf) and
return -EINVAL if true.

Fixes: 74422e2b1939 ("powerpc/pseries: Remove VLA from lparcfg_write()")
Acked-by: Nayna Jain <[email protected]>
Tested-by: R Nageswara Sastry <[email protected]>
Cc: [email protected] # 4.20
Signed-off-by: George Wilson <[email protected]>
---
 arch/powerpc/platforms/pseries/lparcfg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c
index 8821c378bfff..141bc270623e 100644
--- a/arch/powerpc/platforms/pseries/lparcfg.c
+++ b/arch/powerpc/platforms/pseries/lparcfg.c
@@ -697,7 +697,7 @@ static ssize_t lparcfg_write(struct file *file, const char __user * buf,
 	if (!firmware_has_feature(FW_FEATURE_SPLPAR))
 		return -EINVAL;
 
-	if (count > sizeof(kbuf))
+	if (count == 0 || count > sizeof(kbuf))
 		return -EINVAL;
 
 	if (copy_from_user(kbuf, buf, count))
-- 
2.47.3
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